Is this a renewed card with a new number or a totally new card? If it's a renewed card and you use Bank Feed, it's in the Online Setup you change the number.
In your Chart of Accounts go to the CC and Right Click on the account and choose Edit Account. Then click on the Bank Feed Settings tab and choose Deactivate All Online Services. Click on Save & Close.
In Bank Feed the old CC should be gone.
Then go back into the Account and Activate Online Services. During the process you'll have the option to Link to the correct Credit Card account.